Two-dimensional (2D) materials are currently being investigated for use in various semiconductor devices. As used herein, a “two-dimensional material” or “2D material” refers to a crystalline material formed of and including a single (e.g., only one) monolayer of units (e.g., atoms, molecules) bonded together through intramolecular forces (e.g., covalent bonds). Adjacent 2D materials of a structure (e.g., a stack structure) including multiple 2D materials are coupled to one another through one or more intermolecular forces (e.g., Van der Waals forces). Put another way, units (e.g., atoms, molecules) of a single 2D material are coupled to one another through intramolecular forces, and may be coupled to units (e.g., atoms, molecules) of a second 2D material adjacent (e.g., thereover, thereunder) thereto (if any) through intermolecular forces. The thin structure of 2D materials, along with a direct band gap in the visible portion of the electromagnetic spectrum, suggests that 2D materials are suitable for use in a wide variety of digital electronic devices and optoelectronic devices.
Unfortunately, problems associated with conventionally forming 2D materials can reduce the performance and reliability of semiconductor devices (e.g., digital electronic devices, optoelectronic devices) into which the 2D materials are incorporated. For example, conventional methods of forming 2D materials can result in significant crystalline defects within the 2D materials that can negatively impact the properties of semiconductor device structures and semiconductor devices including the 2D materials. For example, conventionally formed 2D materials can exhibit undesirable interstitial and vacancy defects, such as those described by Haldar, S., et al., “A systematic study of structural, electronic and optical properties of atomic scale defects in 2D transition metal dichalcogenides MX2 (M=Mo, W; X=S, Se, Te),” Phys. Rev. B 92, 2015. Such crystalline defects can effectuate non-uniform local electron densities, current leakage, and shallow subthreshold slope in the 2D materials, resulting in unacceptable semiconductor device variation.
It would, therefore, be desirable to have improved methods of forming 2D materials permitting the fabrication of semiconductor device structures and semiconductor devices having improved performance characteristics.